1. Field of the Invention
The present invention relates to an improvement of a flux transfer apparatus for applying flux to a work such as a wiring portion or the like in order to remove oxidized film and to provisionally fix solder balls before the solder balls are mounted on a BGA (ball grid array) or wafer in a solder ball mount apparatus.
The present application is based on Japanese Patent Application No. Hei. 10-288855, which is incorporated herein by reference.
2. Description of the Related Art
As a system for transferring flux to a wiring portion of a wiring board or the like, there are generally known a pin transfer system, a ball dip system, a screen printing system, and a dispenser system. However, each of these systems has defects.
In the pin transfer system, the cost of attachment over a large area is high because individual pins are kept movable, and there is a limit in suitability to a very small pitch. In the ball dip system, since flux is supplied directly to solder balls held by a mount head, the flux is apt to adhere to the mount head when the solder balls are very small.
In the screen printing system, not only the maintenance is very troublesome, but also when there are irregularities in a wiring portion or the like to which flux is to be printed, it is impossible to cope with such irregularities. Further, in the dispenser system, a large number of dispensers are required to cover a large area, so that not only the cost of attachment becomes high impractically, but also variations are produced largely in the technical points.
On the other hand, there is a flux transfer apparatus of a stamp system which is not yet put into practical use. In the stamp system, a projection portion constituted by projections for stamping is formed in a transfer head. In this system, the cost of attachment is small, and the maintenance is easy. There is however a problem in accuracy, for example, such a problem that the stamping projections are apt to come off. In addition, it is impossible for the system to cope with irregularities in a work such as a wiring portion or the like. Accordingly, the stamp system has not been adopted yet.
In order to eliminate the defects of the stamp system, an object of the present invention is to provide a flux transfer apparatus of the stamp system, in which stamping projections are prevented from coming off while it is possible for the apparatus to cope with irregularities in a work such as a wiring portion or the like.
In order to solve the foregoing problem, according to the present invention, there is provided a flux transfer apparatus having a frame having an aperture portion, a mesh stretched across the aperture portion of the frame, and at least one projection on which flux is adhered, the projection being provided on the mesh, and a mesh pitch of the mesh being smaller than a diameter of the projection.
Features and advantages of the invention will be evident from the following detailed description of the preferred embodiments described in conjunction with the attached drawings.